The preferred embodiment concerns a method and a device for determination of the position of a marking of an endless carrier material, the marking serving as a referencing for which the endless carrier material is inserted into a printer or copier to determine a position thereof.
In particular in high-capacity printers with a print speed of greater than 150 sheets of DIN A4 per minute, markings are detected with aid of sensor arrangements in the printer or copier to position print images on the endless carrier material. For example, margin holes provided in a margin region of the carrier material are detected with aid of what are known as hole sensors. Alternatively or additionally, marks pre-printed on the carrier material can be detected with aid of a sensor arrangement (in particular with the aid of a mark sensor) in the printer or copier. With aid of the detected position of such a marking, at least one further position is determined with aid of a control unit of the printer, in particular dependent on a preset form length. The position of a transverse fold present in the carrier material is advantageously determined. The marking or the determined position is positioned at a desired position with aid of the determined position in order to exactly position a print image on the carrier material starting from this desired position.
In order to be able to exactly position further positions on the carrier material (in particular a transverse fold in the carrier material) at a desired position, it is required to detect the position of the transverse fold in relation to the detectable margin holes and/or in relation to the detectable pre-printed marks in order to be able to exactly determine and position the exact bearing of the carrier material in the printer or copier as well as the bearing of further positions, in particular further transverse folds in the carrier material. Workflows are controlled and/or error states are monitored with aid of the detected positions of a marking in the printer or copier.
Given a known high-capacity printer of the model CB by the applicant, a paper web 16 serving as a carrier material is positioned at a position marking after the insertion. As shown in FIG. 1, the position marking is an edge of a guide 12 transverse to the primary transport direction of the paper web 16 that is fastened to a pivotable device 14 such that the guide 12 can be pivoted towards the paper web 16 in the direction of the arrow P1 with the aid of the pivot device 14. In the downward-pivoted state, the lower edge of the guide 12 contacts the surface of the paper web 16 or is arranged directly above the paper web 16 in order to avoid measurement or positioning errors. The paper web 16 is supplied to the printer in the direction of the arrow P2, whereby the direction specified by the arrow P2 is the primary transport direction in which the paper web 16 is supplied to the printer for printing.
The edge of the guide 12 (visible in the downward-pivoted state on the paper web 16) forms the position marking on which a marking applied on the paper web 16 must be exactly aligned in order to implement what is known as a synchronization procedure starting from this position. Given such a synchronization procedure the paper web 16 is conveyed in the direction of the arrow P2 until a marking is detected with the aid of a sensor arrangement arranged in the printer. The further positioning of the paper web 16 in the printer is controlled starting from the length of the paper web 16 transported until the arrival of the marking at the sensor arrangement and the real position of the paper web 16 upon arrival of the marking at the sensor arrangement.
In the present case the paper web 16 comprises a transverse fold 18 that is designed as a perforation in the paper web 16 and forms a separation point between two adjoining, printable forms. The forms are segments of the paper web 16 to be printed, which segments establish the length of a single sheet, for example, given a further processing of the paper web 16.
For positioning of the transverse fold 18, with the aid of operator inputs by an operation personnel the paper web 16 is conveyed back and forth via slow forward transport of the paper web 16 in the direction of the arrow P2 and/or a slow transport of the paper web 16 in the direction opposite the arrow P2 until the transverse fold 18 is exactly aligned on the straight edge of the guide 12. This procedure is relatively elaborate and requires of the operating personnel a great deal of practice and skill. Alternatively or additionally, a marking can be printed on the paper web 16, which marking is also designated as a mark. The mark, similar to the margin holes, is then detected with the aid of a sensor arrangement in the printer or copier, whereby the arrival of the leading or trailing mark edge at the sensor arrangement is advantageously detected and used to control the positioning of the paper web 16.
Furthermore, in FIG. 1 a second transverse fold 20 is shown that, like the first transverse fold 18, is formed as a perforation in the paper web 16. The region between the first transverse fold 18 and the second transverse fold 20 is a print region of a first form.
The paper web 16 with the transverse folds 18 and 20 according to FIG. 1 is shown in FIG. 2. Identical elements have identical reference characters. A first mark 22 in the form of a printed rectangle is shown on the paper web 16. The first mark is arranged immediately after (in relation to the primary transport direction P2 of the paper web 16) the transverse fold 18 in the left margin region of the paper web 16. Given a further processing of the printed paper web 16, this margin region is, for example, cut off or is located in a margin region that is not visible after the binding of a plurality of print pages. A second mark 24 in the form of a rectangle printed on the paper web 16 is arranged immediately after the second transverse fold 20 in the running paper direction P2.
The transverse folds 18 and 20 demarcate a first print region that is also designated as a form, whereby the interval between the transverse folds 18 and 20 is also designated as a form length, A second print region follows the first print region after the transverse fold 20, which second print region has the same form length as the first print region. The second mark 24 is arranged immediately after the second transverse fold 20 and has the same bearing relative to the transverse fold 20 and relative to the left edge of the paper web 16 as the first mark 22 has relative to the transverse fold 18 and to the left edge of the paper web 16.
Starting from the size of the printed marks 22 and 24, a detection range of a sensor arrangement in the printer or copier is provided that, in what is known as a detection window, scans the paper web 16 and determines whether and, if applicable, when a mark edge enters into this detection window at the sensor arrangement. This window is designated with 26 for the first mark 22 in FIG. 2 and with 28 for the second mark 24. However, the window merely specifies the region of the paper web that is scanned with the aid of the sensor arrangement on the basis of the dimensions and position of the marks 22, 24 and is thus visible on the paper web 16 neither before nor after the printing.
After the insertion of the paper web 16 into the printer, the leading mark edge is to be exactly aligned on the straight edge of the guide 12 via slow forward and/or backward movement of the paper web 16. The operating personnel must subsequently measure the bearing and width of the mark 24 aligned on the guide, which mark is transverse to the primary transport direction P2, and input the bearing and width into the printer via a control panel. The sensor arrangement for detection of the mark in the printer is then correspondingly displaced transverse to the primary transport direction such that the mark 24 is detected from the detection region of the sensor arrangement upon passage of the paper web 16 through the printer.
Alternatively or additionally, the detection region of the sensor arrangement can be adapted in the y-direction to the position of the mark 24. The interval between the mark edge facing towards the transverse fold 18 and the transverse fold 18 is also preset as a parameter in the printer, for example via an input by an operating personnel via an input unit. The interval between the transverse fold 18 and the transverse fold 20 (i.e. the form length) or the interval between the leading edge of the first mark 22 and the leading edge of the second mark 24 is also likewise preset as a parameter via an input by the operating personnel.
Primarily the exact positioning of the marking to be detected (i.e. of the mark 24 or of the transverse fold 18) at the guide 12 and the exact dimensioning of the width and the bearing of the mark 24 is quite elaborate and requires a relatively large amount of time even given trained expert personnel. Errors upon measurement and input of the values read off at the guide 12 can also occur.
Alternatively, the marks 22 and 24 can be arranged at an arbitrarily different point of each form. For example, the marks 22 and 24 can be used as graphical elements for the overall print image to be generated and in particular can be components of a logo.
Arrangements that detect position markings provided on a carrier material to be printed are known from the documents U.S. Pat. No. 6,292,649 B1, U.S. Pat. No. 6,256,474 B1, U.S. Pat. No. 5,929,894 and EP 0 443 590 A1.